The past decade has witnessed a revolution in our understanding of human body homeostasis based on cellular communication. Advances in our comprehension of the development and expansion of several pathologies are largely due to our increased understanding of the biological roles of EVs, with a particular focus on exosomes.
The increasing amount of data on the composition, biogenesis, and roles of exosomes in physiology and pathology has created new possibilities in diagnosis and therapy. Exosomes have unique characteristics that result from their cellular origin which make them valuable as new biomarkers for diagnosis, stratification and planning, and for treatment efficacy evaluation. Their molecular composition, in terms of both their membrane and cargo, includes lipids, proteins, and nucleic acids, providing information about their cells of origin and their status. Our ability to now acquire this valuable cellular information and the fact that it also comes from hard-to reach tissues, has resulted in the term ‘liquid biopsy’, a new frontier in the clinical field.
In addition, exosomes combine the advantages of nanocarriers (i.e., particles used to efficiently deliver molecules) and therapeutic agents. Exosomes are currently considered among the most promising drug delivery systems, especially for gene therapy in different disorders (such as genetic deficiencies or antitumor progression). Several studies have been published during the past 5 years regarding the modification of targeting moieties and/or the encapsulation of endogenous and exogenous material in exosomes, pre or post isolation from cell cultures. These studies represent the development of so-called ‘exosome-based semisynthetic nanovesicles (NVs)’, a subtype of artificial exosomes that includes all exosomes with modifications for specific purposes. They have even been tested for autologous therapy, using the patient’s own immune cells (cultured and expanded outside the body) as a source of exosomes.
Despite the great expansion of techniques for developing semisynthetic exosomes, the main drawbacks concerning their clinical application include production, isolation, modification, and purification on a large scale and at a suitable clinical grade. However, these drawbacks have resulted in the design and manufacture of fully synthetic exosome-mimetic particles using bionanotechnology. University of Oviedo researchers provide an overview of these techniques, organized according to two trends in nanofabrication: top-down and bottom-up approaches.